Autotransformer



July 26, 1966 c. B. VAUGHAN 3,263,195

AUTOTRANSFORMER Original Filed Jan. 15, 1962 INVENTOR.

N CARROLL B. M4UGHAN .rate auto transformer for each output channel.

United States Patent 3,263,195 AUTOTRANSFORMER Carroll B. Vaughan, EastOrange, N.J., assignor to The Bendix Corporation, a corporation ofDelaware Original application Jan. 15, 1962, Ser. No. 166,224.

Divided and this application Aug. 6, 1963, Ser. No. 300,312 I 2 Claims.(Cl. 336-45) The present application is a division of US. applicationSerial No. 166,224, filed January 15, 1962, by Carroll B. Vaughan andassigned to The Bendix Corporation and the invention relates in generalto an autotransformer and more particularly to a multi tap autotransformer having a plurality of independently variable outputterminals. I

Heretofore, a number of devices were available to supply from a singlealternating current source, a plurality of independently adjustablealternating currents on a plurality of channels. These devices used asepa;

Or, i there was a predetermined relationship between the alternatingcurrents to be provided at two channels, a single auto transformer wasused, with two brushes mechanically linked together.

The present invention is a multi independent brush auto transformer thatprovides a plurality of independently adjustable alternating currents ona plurality of channels with the use of only a single magnetic core anda single source of alternating current. Some of the advantages of thenovel multi independent brush auto transformers are compactness,efficiency, and the ability to avoid saturation of the core when theoutput voltage is half wave rectified.

The ability to avoid saturation of the magnetic core is inherent to themulti tap. auto transformers. Saturation occurs when the output of anauto transformer feeds a half wave load. However, the multi tarp autotransformer can feed several half wave loads, one on each of its outputterminals. The half wave loads can be adjusted so that the loads at someterminals will be of one polarity while the load at the other terminalswill be of the other polarity, thus avoiding saturation of the magneticcore.

An object of the invention is in the provision of a novel multi channelpower supply.

Another object of the invention is in the provision of a novel multipletap auto transformer having several output channels, each output voltagebeing independently adjustable.

Another object of the present invention is in the provision of a-novelalternating current power supply having a multiplicity of outputterminals; the voltage at each terminal being continuously adjustableand adjustable independently of each other.

Another object of the invention is in the provision of a novelalternating current power supply having a plurality of independentlyadjustable output voltages taken off a single core auto transformer. I

Another object of the present invention is in the provision of a novelauto transformer having a plurality of independently adjustable outputterminals to provide a compact alternating current power supply.

Another object of the invention is to provide a novel independent brushauto transformer having a plurality of output terminals to avoidsaturation of the core during half Wave loading of the outputs.

These and other objects and features of the invention are pointed out inthe following description in terms of the embodiment thereof which isshown in the accompanying drawings. It is to be understood, however,that the drawings are for the purpose of illustration only ice and arenot a definition of the limits of the invention, reference being had tothe appended claims for this purpose.

FIGURE 1 is an exploded view of the operative parts of a multi variablebrush auto transformer of the present invention.

FIGURE 2 is a detailed view of a spring loaded brush and brush holder ofthe multi variable, brush auto transformer shown in FIGURE 1.

The present invention relates to a novel multi inde pendent brush autotransformer (or alternating current power supply, one embodiment ofwhich is shown by FIGURES 1 and 2.

Referring to FIGURE 1, there is shown therein an exploded view of theoperative parts of the novel multi independent brush auto transformer.In particular, a toroid 201 is wound with a wire 202 in a single layerover its outside cylindrical surface so as to provide an exposedsegmental wire contact or commutator surface 203 of a wire wound toroid,as described and claimed in a copending U.S. application Serial No.315,735, filed September 25, 1965, by Carroll B. Vaughan as a divisionof US. application Serial No. 166,343, filed January 15, 1962 by CarrollByrd Vaughan, now US. Patent No. 3,213,520 granted October 26, 1965, toCarroll B. Vaughan for method for preparing a toroid core, and assignedto The Bendix Corporation, assignee of 'the present application. In theFIGURE 1, the wire is shown covering approximately 330 of the outsidesurface.

Two ends 218, 219, of the wire 202 to be connected to an alternatingcurrent source are brought out to two terminals 220 and 221 on a toroidframe (not shown). A ring gear 222 (having an inside diameter of, forexample, approximately 3% inches, and an outside diameter of, forexample, approximately 4 /2 inches with 10 teeth per inch on its outerdiameter) fits over the toroid 201. The toroid 201 is securely mountedon a rigid frame (not shown) and has an outside diameter of, forexample, approximately 3 inches.

The toroid 201 projects from the rigid frame in a spaced concentricrelation within the larger annular openingof the ring gear 222. The ringgear 222 is rotatably positioned, in a supporting member of aconventional type formed of a suitable electrical insulating materialand carried by the rigid frame.

A brush 223, held by a brush holder 226, makes a variable operativeelectrical contact with commutator sur- 7 face 203 and is mounted in aslot 224 located in the wall of the gear 222 and is capable of movingradially in the gear under the constraint of the slot 224, springloading means 225, and the brush holder 226. A detailed view of thespring loading 22'5, brush 223, and brush holder 226 is shown in FIGURE2. The brush 223 is, for example, approximately by ,4 by of an inch,andthe ring gear 222 has a width, for example, of of an inch. A flexiblemetal pigtail conductor 226 leads from the brush holder 226 to the metalring gear 222. Thus, there is a conducting path from the input wireterminals 220 and 221, of the toroid 201 through the toroid windings 202and commutator surface 203 to the brush 223, brush holder 226, andpigtail conductor 226' into the ring gear 222.

Ring gear 222 rides next to a wrinkle spring washer 227 made of aconducting material and supported in a fixed relation by the supportingmember of insulating material carried by the rigid frame (not shown). Apigtail conductor 229 is soldered to the wrinkle washer 227 and broughtout to a terminal lug (not shown) on the frame (not shown). Aninsulating ring washer 228 also supported by the supporting member ofthe frame (not shown) and having the same dimension as the ring gear 222is then stacked next to the wrinkle spring washer 227.

The ring gear 222 may be adjusted in slidable relation to the Wrinklespring washer 227 which serves to hold the ring gear 227 and washer 228under spring tension in a compact relation in the assembled device.

What has been just described, namely the ring gear 222 brush 223,wrinkle washer 227, and insulating ring 228 comprise one of manyassemblies which are to be mounted in the supporting member of the rigidframe (not shown) of the multi independent brush auto transformer. Inthe present embodiment, 10 such assemblies are installed around thecenter toroid 201. It should be noted that the multiple brush autotransformer may comprise any number of outputs, depending on the lengthof the toroid 201 and the number of assemblies.

The toroid 201 is securely mounted on the rigid frame (not shown) andsurrounded by a housing (not shown).

The wire 202 on the toroid 201 is connected at its ends 218 and 219 totwo terminals 220 and 221 mounted on the outside of the frame andhousing.

The brushes 223 are positioned by rotation of the ring gear 222. Thisgear 222 is rotated by means of a worm gear 230 mounted on a shaft 231terminating in a crank 232 which may be of a suitable electricalinsulating material. By revolving the crank 232, the worm gear 230causes the ring gear 222 to rotate in the suitable supporting meanscarried by the rigid frame and surrounded by the housing (not shown).

The location of the brush 223 on the toroid commutator surface 203 isproportional to the number of revolutions of the crank 232 and isindicated on. a flat slide rule indicator 235. A string 237 winds andunwinds with the direction of rotation of the crank 232. The string islead over a small pulley 237A and actuates pointer 236 on the slide ruleindicator 235. A spring 239 or other restoring force returns the pointer236 to the zero position when the brush is at a minimum position. As thecrank 232 is turned, a rack and pinion arrangement advances a slottedshaft 234 with an eyelet 233 to guide the string 237, in order that thestring will not slack up on the crank shaft 232, but will lay in eventurns. There may be a plurality of such gear and brush assembly, andthere is one indicating device for each gear and brush assembly and eachslide rule indicator 235 may be calibrated in either percentages orproportional to the output voltage.

Although only one embodiment of the invention has been illustrated anddescribed, various changes in the form and relative arrangement of theparts, which will now appear to those skilled in the art may be madewithout departing from the scope of the invention. Reference is,therefore to be had to the appended claims for a definition of thelimits of the invention.

What is claimed is:

1. A multi tap auto transformer comprising a toroid core of magneticmaterial; a wire winding on said core of a commutator type; a pluralityof adjacently placed brush groups each including a rotatablypositionable ring gear mounted concentrically on the toroid; aconducting wrinkle ring washer mounted concentrically on the toroid andadjacent to and in electrical contact with the ring gear; an insulatingring washer mounted concentrically on the toroid and adjacent to thewrinkle ring washer; a brush carried on the ring gear and extendingradially on said gear to make contact with the commutator surface on thewire winding; and operator-operative positioning means for rotating saidring gear about the toroid to adjustably position :the brush carried bysaid ring gear relative to said commutator surface on the wire winding.

2. The combination defined by claim 1 including a worm gear operativelyconnected to the ring gear, an operator-operative shaft on the wormgear; a string means having two ends; one end of said string means beingattached to the shaft and the other end of said string means beingattached to a spring loading means, an indicating member located at afixed position on the string means, intermediate the ends thereof; anindicating panel located in spaced relation to said indicating memberwhereby upon the worm gear being actuated to adjustably position thering gear and the shaft of the worm gear being rotated, the string meansmay be effectively wound about said shaft so as to displace said stringand the indicating member fixed thereto, said displacement of the saidindicating member being observable on the indicating panel, and saidstring means and indicating member displacement being proportional tothe adjusted position of the ring gear.

References Cited by the Examiner UNITED STATES PATENTS 2,061,452 11/1936Comstock et al. 336l49 X 3,132,627 5/1964 Lesatz l16-l24 FOREIGN PATENTS263,829 7/1927 Great Britain.

LARAMIE E. ASKIN, Primary Examiner.

JOHN-F. BURNS, Examiner.

C. TORRES, Assistant Examiner.

1. A MULTI TAP AUTO TRANSFORMER COMPRISING A TOROID CORE OF MAGNETIC MATERIAL; A WIRE WINDING ON SAID CORE OF A COMMUTATOR TYPE; A PLURALITY OF ADJACENTLY PLACED BRUSH GROUPS EACH INCLUDING A ROTATABLY POSITIONABLE RING GEAR MOUNTED CONCENTRICALLY ON THE TOROID; A CONDUCTING WRINKLE RING WASHER MOUNTED CONCENTRICALLY ON THE TOROID AND ADJACENT TO AND IN ELECTRICAL CONTACT WITH THE RING GEAR, AN INSULATING RING WASHER MOUNTED CONCENTRICALLY ON THE TOROID AND ADJACENT TO THE WRINKLE RING WASHER; A BRUSH CARRIED ON THE RING GEAR AND EXTENDING RADIALLY ON SAID GEAR TO MAKE CONTACT WITH THE COMMUTATOR SURFACE ON THE WIRE WINDING; AND OPERATOR-OPERATIVE POSITIONING MEANS FOR ROTATING SAID RING GEAR ABOUT THE TOROID TO ADJUSTABLY POSITION THE BRUSH CARRIED BY SAID RING GEAR RELATIVE TO SAID COMMUTATOR SURFACE ON THE WIRE WINDING. 